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#include "lisc.h"
static void
addpred(Blk *bp, Blk *bc)
{
uint i;
if (!bc->pred) {
bc->pred = alloc(bc->npred * sizeof bc->pred[0]);
for (i=0; i<bc->npred; i++)
bc->pred[i] = 0;
}
for (i=0; bc->pred[i]; i++)
;
bc->pred[i] = bp;
}
/* fill predecessors information in blocks
*/
void
fillpreds(Fn *f)
{
Blk *b;
for (b=f->start; b; b=b->link) {
b->npred = 0;
free(b->pred);
b->pred = 0;
}
for (b=f->start; b; b=b->link) {
if (b->s1)
b->s1->npred++;
if (b->s2)
b->s2->npred++;
}
for (b=f->start; b; b=b->link) {
if (b->s1)
addpred(b, b->s1);
if (b->s2)
addpred(b, b->s2);
}
}
static int
rporec(Blk *b, int x)
{
Blk *s1, *s2;
if (!b || b->id >= 0)
return x;
b->id = 1;
s1 = b->s1;
s2 = b->s2;
if (s1 && s2 && s1->loop > s2->loop) {
s1 = b->s2;
s2 = b->s1;
}
x = rporec(s1, x);
x = rporec(s2, x);
b->id = x;
assert(x >= 0);
return x - 1;
}
/* fill the rpo information in blocks
*/
void
fillrpo(Fn *f)
{
int n;
Blk *b, **p;
for (b=f->start; b; b=b->link)
b->id = -1;
n = 1 + rporec(f->start, f->nblk-1);
f->nblk -= n;
free(f->rpo);
f->rpo = alloc(f->nblk * sizeof f->rpo[0]);
for (p=&f->start; *p;) {
b = *p;
if (b->id == -1) {
*p = b->link;
/* todo, free block */
} else {
b->id -= n;
f->rpo[b->id] = b;
p=&(*p)->link;
}
}
}
/* gets the representant for the phi class of t
*/
int
phirepr(Tmp *tmp, int t)
{
int tp;
tp = tmp[t].phi;
if (tp == 0)
tp = t;
else if (tp != t) {
tp = phirepr(tmp, tp);
tmp[t].phi = tp;
}
return tp;
}
/* fill union find data for phi classes
* requires live
*/
void
fillphi(Fn *fn)
{
Blk *b;
Phi *p;
uint a;
int t, ta;
Tmp *tmp;
tmp = fn->tmp;
for (t=Tmp0; t<fn->ntmp; t++)
tmp[t].phi = 0;
for (b=fn->start; b; b=b->link)
for (p=b->phi; p; p=p->link) {
t = p->to.val;
if (tmp[t].phi == 0)
tmp[t].phi = t;
for (a=0; a<p->narg; a++) {
if (rtype(p->arg[a]) != RTmp)
continue;
ta = p->arg[a].val;
if (BGET(b->in, ta))
/* do not merge the
* classes of phi args
* that outlive the phi
* node
*/
continue;
ta = phirepr(tmp, ta);
tmp[ta].phi = t;
}
}
}
static Ref *top, *bot;
static Ref topdef(Blk *, Fn *, int);
static Ref
botdef(Blk *b, Fn *f, int w)
{
Ref r;
if (!req(bot[b->id], R))
return bot[b->id];
r = topdef(b, f, w);
bot[b->id] = r;
return r;
}
static Ref
topdef(Blk *b, Fn *f, int w)
{
uint i;
int t1;
Ref r;
Phi *p;
if (!req(top[b->id], R))
return top[b->id];
assert(b->npred && "invalid ssa program detected");
if (b->npred == 1) {
r = botdef(b->pred[0], f, w);
top[b->id] = r;
return r;
}
/* add a phi node */
t1 = f->ntmp++;
r = TMP(t1);
top[b->id] = r;
p = alloc(sizeof *p);
p->link = b->phi;
b->phi = p;
p->to = r;
p->wide = w;
for (i=0; i<b->npred; i++) {
p->arg[i] = botdef(b->pred[i], f, w);
p->blk[i] = b->pred[i];
}
p->narg = i;
return r;
}
/* restore ssa form for a temporary t
* predecessors must be available
*/
void
ssafix(Fn *f, int t)
{
uint n;
int t0, t1, w;
Ref rt;
Blk *b;
Phi *p;
Ins *i;
w = 0;
top = alloc(f->nblk * sizeof top[0]);
bot = alloc(f->nblk * sizeof bot[0]);
rt = TMP(t);
t0 = f->ntmp;
for (b=f->start; b; b=b->link) {
t1 = 0;
/* rename defs and some in-blocks uses */
for (p=b->phi; p; p=p->link)
if (req(p->to, rt)) {
t1 = f->ntmp++;
p->to = TMP(t1);
w |= p->wide;
}
for (i=b->ins; i-b->ins < b->nins; i++) {
if (t1) {
if (req(i->arg[0], rt))
i->arg[0] = TMP(t1);
if (req(i->arg[1], rt))
i->arg[1] = TMP(t1);
}
if (req(i->to, rt)) {
w |= i->wide;
t1 = f->ntmp++;
i->to = TMP(t1);
}
}
if (t1 && req(b->jmp.arg, rt))
b->jmp.arg = TMP(t1);
top[b->id] = R;
bot[b->id] = t1 ? TMP(t1) : R;
}
for (b=f->start; b; b=b->link) {
for (p=b->phi; p; p=p->link)
for (n=0; n<p->narg; n++)
if (req(p->arg[n], rt))
p->arg[n] = botdef(p->blk[n], f, w);
for (i=b->ins; i-b->ins < b->nins; i++) {
if (req(i->arg[0], rt))
i->arg[0] = topdef(b, f, w);
if (req(i->arg[1], rt))
i->arg[1] = topdef(b, f, w);
}
if (req(b->jmp.arg, rt))
b->jmp.arg = topdef(b, f, w);
}
/* add new temporaries */
f->tmp = realloc(f->tmp, f->ntmp * sizeof f->tmp[0]);
if (!f->tmp)
diag("ssafix: out of memory");
for (t1=t0; t0<f->ntmp; t0++) {
f->tmp[t0] = f->tmp[t];
snprintf(f->tmp[t0].name, NString, "%s%d",
f->tmp[t].name, t0-t1);
}
free(top);
free(bot);
}
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